This invention is concerned with predicting the maintenance necessary on machinery. Heretofore it has been conventional to schedule machine maintenance by period of use, but this may result in much unnecessary maintenance and down time on machines requiring no maintenance. Another common method for scheduling maintenance is that by analysis of used lubricant, but this may be expensive, involve substantial time for processing the lubricant, and may indicate only one of many parts being worn.
Also commonly employed to indicate the need for machine maintenance is vibration analysis. However, this method does not distinguish between systemic vibration and that resulting from small defects, but may obscure the latter. There have been attempts to detect machine defects by picking up and analyzing vibrational waves, but these have not proved satisfactory. They tend to cause false alarms resulting in unnecessary maintenance, and on the other hand to mask defects prior to machine failure.
Among the prior patents of this type, of which applicant is aware, are those listed below:
______________________________________ U.S. PAT. NO. PATENTEE ______________________________________ 3,554,012 Sohoel 3,712,130 Weichbrodt et al. 4,007,630 Noda ______________________________________